A circuit board or module of a computer typically will have many solid state electrical devices, such as chips, mounted on the module, all of which are designed to operate at fixed logic level voltages. In the proper operation of the circuit, these chips need to be supplied with power at the required logic level voltages, for example 3.3 volts or 5 volts. In addition, both the magnitude of these logic voltages and their device to device voltage differentials must be held within a tightly specified range.
The usual method for distributing power to the individual chips from a computer power supply is to regulate the power from, high voltages DC to the logic level voltages required by the chips, in a location remote from the module. The power is regulated from high-voltage and low current to low-voltage and high current. This low-voltage and high current power is then supplied from the remote location over a power bus to the module containing the plurality of chips. On the module, the power is then distributed to each of the individual chips on that module.
A prime consideration for the designer is the fact that conduction of high current at low-voltages over a long distance will produce more electrical and thermal losses, and electrical distortion than conduction over a short distance. Therefore, the closer the power regulators are to the chips themselves, the lower the amount of losses and voltage distortion that will occur.
In packaging electronic modules, one of the additional design concerns that must be taken into consideration is any detrimental by-products generated by the operation of the chips and the regulators, for example, electromagnetic interference (EMI) and thermal heating. Electromagnetic interference, produced by the power regulators, can disturb the operation of nearby electronic equipment such as telecommunications, sensitive computer circuitry, and even other power circuits. As a result, there are strict federal and international standards imposed on the level of conducted and radiated EMI permitted in commercial products. Therefore, there must be provisions for EMI shielding when designing a module package. In addition, provision must be made to dissipate the heat generated by both the chips and the regulators, and various means have been utilized to do so, such as the use of heat convection and heatsinks.
A new high power density point-of-load regulator has been developed that is of such a size as to allow the regulator to be placed on a module, close to the chips in a compact 3-Dimensional packaging configuration. Such a regulator is supplied with low current and high-voltage power and regulates this to the high current and low-voltage power needed by the chips. When a point-of-load regulator is mounted on the module itself, the power only has to be conducted a short distance to the individual chips or loads. At present, the designs for mounting these point-of-load regulators on the modules require considerable module area.
Thus, a need exists to package these new high density point-of-load regulators, by providing necessary mechanical support, heat dissipation and EMI shielding in a compact module-mounted configuration.